1. Technical Field
The present invention relates to an optical position detecting device which optically detects a target object.
2. Related Art
An optical position detecting device has been suggested for optically detecting a target object, for example, by emitting detection light toward the target object via a translucent member from two detection light source sections, and detection light reflected by the target object is transmitted through the translucent member and is detected by a photodetector. In such an optical position detecting device, for example, if the two detection light source sections are differentially moved on the basis of the detection result in the photodetector, the ratio of the distance between one light source section for detection of the two detection light source sections and the target object and the distance between the other light source section for detection and the target object is known. Accordingly, the position of the target object can be detected (refer to JP-T-2003-534554).
However, in the configuration described in JP-T-2003-534554, the emitting space of the detection light is fixed. Therefore, there are the following problems. First, even in a case where it is known in advance that the target object is present within a narrow range, it is necessary to emit the detection light with an illuminance higher than a predetermined value over a wide range. Therefore, there is a problem in that electric power is wastefully consumed. Additionally, since the emitting space of the detection light is fixed, even in a case where a target object only in a specific space is detected, there is a problem in that a target object within the entire emitting space may be detected.